Blind rivet-nut and method for securing a component to a carrier

ABSTRACT

A blind rivet-nut having an annular-flange-like setting head and a hollow shaft for securing a blind rivet-nut in an opening of a carrier. The hollow shaft has a free end having a threaded portion for receiving a threaded element of a tensioning tool. A clamping portion adjacent to the setting head forms a bead-like deformation when the tensioning tool is used to clamp the carrier between the bead-like deformation and the setting head. A threadless shaft portion is formed between the clamping portion and the threaded portion. The threadless shaft portion is threaded by a thread self-rolling or thread self-tapping fastener. The fastener is received in a positive-locking manner when the fastener is screwed into the thread formed on the previously threadless shaft portion. A method is also disclosed for securing a component to a carrier by a blind rivet-nut.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under 35 U.S.C.§119(a)-(d) to DE 10 2016 212 024.7 filed Jul. 1, 2016, which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a blind rivet-nut for securing acomponent to a carrier by means of a blind rivet-nut and a method forsecuring a component to a carrier by means of a blind rivet-nut.

BACKGROUND

A blind rivet-nut set on a carrier, in particular a component producedfrom sheet metal, is intended to be securely connected in order toprovide it with a securing thread which can be used to secure a bolt ora screw. Blind rivet-nuts can further serve to connect two or morethin-walled carriers or components to each other.

A rivet-nut comprises a setting head which is intended to contact afirst side of the carrier and a hollow shaft which is configured to beinserted in a through-hole of the carrier. The hollow shaft comprises aclamping portion which is intended, under the action of an axial pullingforce, to become deformed to form a bead which moves into abutment withthe second side of the carrier so that the carrier is clamped to ensurethe retention of the nut on the carrier. Furthermore, the nut is set ina blind manner the nut is set in the region of the second side of thecarrier without access to this second side. Generally, the shaft of ablind rivet-nut comprises a threaded portion for receiving a threadedelement, wherein the threaded element enables the axial pulling forcewhich is required to deform the clamping portion to be applied to thehollow shaft. This threaded portion is subsequently used to screw in ascrew or a bolt which is intended to be secured to the blind rivet-nut.Such a blind rivet-nut is known, for example, from DE 20 2015 100 359U2.

The screwing of the threaded element into the threaded portion requiresprecise straight positioning and centering of the threaded element onthe threaded portion so that the threaded element is not placed in anoblique manner on the thread and consequently becomes jammed during thescrewing-in operation.

SUMMARY

Against this background, an object of the present invention is toprovide a blind rivet-nut which is improved with respect to use duringlarge-batch production and in which tilting and jamming of a screw or abolt which is intended to be secured to the blind rivet-nut is preventedduring screwing into the blind rivet-nut to the greatest possibleextent. Furthermore, a securing arrangement and a securing method havingthe same advantageous properties are intended to be set out.

It should be noted that the features which are set out individually inthe claims can be combined with each other in any technicallyadvantageous manner and set out other embodiments of the invention. Thedescription further characterizes and specifies the invention withspecific references to the Figures.

According one aspect of the invention, a blind rivet-nut for blindriveting in an opening of a carrier comprises, for example, athin-walled metal sheet, an annular-flange-like setting head and ahollow shaft. The hollow shaft has at the free end thereof opposite thesetting head a threaded portion for receiving a threaded element, forexample, a screw or a bolt, and a clamping portion which is adjacent tothe setting head. The clamping portion is intended, during a settingoperation of the blind rivet-nut on the carrier, to become deformed in abead-like manner in order thus to clamp the carrier between thebead-like deformation of the clamping portion and the setting head. Theinvention further makes provision for an additional threadless shaftportion to be formed in the hollow shaft between the clamping portionand the threaded portion. This threadless shaft portion is suitable andconstructed for receiving a thread self-rolling or thread self-tappingscrew or bolt in a positive-locking manner therein when the screw/boltis screwed into the shaft portion.

The term thread self-rolling is intended to be understood to be anon-cutting introduction of a thread by means of the screw or the boltinto the thread-free shaft portion of the blind rivet-nut when it isscrewed into the threadless shaft portion, whereas a thread self-tappingoperation is intended to be understood to be introduction involvingcutting of the thread by means of the screw or the bolt into thethreadless shaft portion of the blind rivet-nut when it is screwed intothe threadless shaft portion. As used herein the term “self-tapping” isintended to refer to both self-rolling and self-tapping fasteners. Apositive-locking receiving of the screw or the bolt in the shaft portionis produced when the screw or the bolt has introduced the thread intothe threadless shaft portion and the screw or the bolt is screwed intothis thread. The screw or the bolt serves, for example, to secureanother component to the blind rivet-nut or to the carrier.

A specific advantage of the blind rivet-nut according to the inventionis that the securing screw or the securing bolt can neither tilt norbecome jammed when it is screwed into the threadless shaft portion sinceit forms the thread itself only when it is screwed into the threadlessshaft portion. Furthermore, the threadless shaft portion advantageouslyleads to a self-centering of the securing screw or the securing bolt inthe threadless shaft portion of the blind rivet-nut during thescrewing-in operation.

An advantageous embodiment of the invention makes provision for thethreadless shaft portion to have a hole diameter which is smaller thanthe diameter of the clamping portion and greater than the diameter ofthe threaded portion. It can thereby be ensured that only the clampingportion with the largest hole diameter becomes plastically deformedduring a setting operation of the blind rivet-nut on the carrier, butnot the threadless shaft portion and the threaded portion.

The wall thickness of the threadless shaft portion may be sized in sucha manner in this instance that the threadless shaft portionsubstantially does not become plastically deformed during the settingoperation of the blind rivet-nut on the carrier.

Furthermore, the wall thickness of the threadless shaft portion mayalways be sized in such a manner that an inner thread can be rolled orcut in this shaft portion. In this instance standards for formingthreads known per se to the person skilled in the art can be consideredand complied with.

According to another aspect of the present invention, there is provideda securing arrangement which has a component which is secured to acarrier by means of a blind rivet-nut, wherein the blind rivet-nut isblind-riveted in conventional manner in an opening of the carrier andthe component is secured to the blind rivet-nut by means of a screw or abolt. In this instance, the invention makes provision for the blindrivet-nut to be constructed in accordance with one of the embodimentsdescribed above. Furthermore, the screw or the bolt is a threadself-rolling or thread self-tapping screw or bolt and this screw or boltis screwed into the shaft portion of the blind rivet-nut, which portionis threadless before the screwing-in operation, to form apositive-locking receiving member therein for itself.

Other embodiments of the securing arrangement according to the inventionwhose advantages and effects will be appreciated directly from thepreceding description of the blind rivet-nut according to the inventionand can accordingly also be applied to the securing arrangement.

According to yet another aspect of the present invention, a method forsecuring a component to a carrier by means of a blind rivet-nut which isconstructed in accordance with one of the embodiments described above isprovided. The method has at least the following steps: setting the blindrivet-nut in an opening of the carrier so that the clamping portion ofthe blind rivet-nut becomes deformed in a bead-like manner during thesetting operation of the blind rivet-nut and the carrier is clampedbetween the bead-like deformation of the clamping portion and thesetting head of the blind rivet-nut; and securing the component to theblind rivet-nut by screwing a screw or a bolt into the shaft portion ofthe blind rivet-nut, which portion is threadless before being screwedin, wherein the screw or the bolt is thread self-rolling or threadself-tapping in order to form a positive-locking receiving member foritself in the threadless shaft portion.

In this instance, there are also produced additional embodiments of thesecuring method according to the invention, whose advantages and effectsdirectly from the preceding description of the blind rivet-nut accordingto the invention and can accordingly also be applied to the securingmethod.

Other features and advantages of the invention will be appreciated fromthe following description of an embodiment (which is not intended to beunderstood to be limiting) of the invention which will be explained ingreater detail below with reference to the drawings. In the schematicdrawings:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section of an embodiment of a blind rivet-nutaccording to the invention before a setting operation on a carrier,

FIG. 2 is a cross-section of the blind rivet-nut from FIG. 1 after thesetting operation on the carrier, and

FIG. 3 is a cross-section of the blind rivet-nut from FIG. 2 which isset on the carrier and to which another component is secured.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention that may be embodied in variousand alternative forms. The figures are not necessarily to scale; somefeatures may be exaggerated or minimized to show details of components.Therefore, specific structural and functional details disclosed hereinare not to be interpreted as limiting, but merely as a representativebasis for teaching one skilled in the art to variously employ thepresent invention.

In the different Figures, components which are equivalent in terms oftheir function are always given the same reference numerals so that theyare generally also described only once.

FIG. 1 is a cross-section of an embodiment of a blind rivet-nut 1 madeaccording to this disclosure before a setting operation on a carrier 2.FIG. 1 shows that the blind rivet-nut 1 has an annular-flange-likesetting head 3 and a hollow shaft 4 which is integrally connected to andadjacent to the setting head 3.

The hollow shaft 4 of the blind rivet-nut 1 illustrated in FIG. 1comprises at the free end thereof opposite the setting head 3 a threadedportion 5 for receiving a threaded element 6 which is fitted, forexample, to a tension screw 7 as shown in FIG. 1. The tension screw 7serves to set the blind rivet-nut 1 on the carrier 2, as will be furtherexplained with reference to FIG. 2.

Furthermore, the hollow shaft 4 has a clamping portion 8 adjacent to thesetting head 3 that deforms in a bead-like manner during a settingoperation of the blind rivet-nut 1 on the carrier 2. The bead-likedeformation 9 of the clamping portion 8 clamps the carrier against thesetting head 3, as illustrated in FIG. 2.

In the embodiment of the blind rivet-nut 1 illustrated in FIG. 1, athreadless shaft portion 10 is constructed between the clamping portion8 and the threaded portion 5. This threadless shaft portion 10, orsleeve, is constructed to receive a thread self-rolling or threadself-tapping screw 11 or bolt in a positive-locking manner when thescrew/bolt is screwed into the shaft portion 10, as illustrated in FIG.3.

FIG. 1 further shows that the threadless shaft portion 10 has a holediameter 12 which is smaller than the diameter 13 of the clampingportion 8 and greater than the diameter 14 of the threaded portion 5.The hollow shaft 4 of the blind rivet-nut 1 as shown in FIG. 4 has asubstantially constant outer diameter along the clamping portion 8, thethreadless shaft portion 10 and the threaded portion 5. Different wallthicknesses are provided for the clamping portion 8, the threadlessshaft portion 10 and the threaded portion 5. The wall thickness of thethreadless shaft portion 10 is sized in such a manner that an innerthread can be rolled or cut in the threadless shaft portion 10. Theblind rivet-nut 1 when set on the carrier 2 plastically deforms theclamping portion 8 but does not plastically deform the threadless shaftportion 10 during the setting operation.

As indicated in FIG. 1, the blind rivet-nut 1 is first introduced intothe opening defined by the carrier 2 and a suitable setting tool, suchas a tension screw 7 is used to set the blind rivet-nut 1. The threadedelement 6 of the tension screw 7 is screwed into the threaded portion 5of the blind rivet-nut 1 to apply an axial pulling force to the hollowshaft 4 of the blind rivet-nut 1.

FIG. 2 is a cross-section of the blind rivet-nut 1 from FIG. 1 aftersetting the blind rivet-nut on the carrier 2. The clamping portion 8 ofthe blind rivet-nut 1 is plastically deformed by the axial pulling forceapplied by the tension screw 7. The plastic deformation creates thebead-like deformation 9 of the clamping portion 8. The carrier 2 isclamped between the bead-like deformation 9 of the clamping portion 8and the setting head 3 after the setting operation.

FIG. 3 is a cross-section of the blind rivet-nut 1 of FIG. 2 set on thecarrier 2 and to which another component 15, for example, a metal sheet,is secured by means of the securing screw 11. The thread self-rolling orthread self-tapping securing screw 11 is screwed into the shaft portion10 to secure the component 15 to the blind rivet-nut 1 or to the carrier2. The shaft portion 10 is threadless before the self-tapping screw isscrewed into the shaft portion 10. The self-tapping screw forms, rollsor cuts a thread into shaft portion 10 and the screw 11 is received in apositive-locking manner in the thread.

The blind rivet-nut according to the invention is used to secure acomponent to a carrier by means of a thread self-rolling or threadself-tapping screw or bolt. The blind rivet-nut, the securingarrangement and the securing method are, however, not limited to theembodiment described herein, but instead also include other embodimentswhich have the same effect.

While exemplary embodiments are described above, it is not intended thatthese embodiments describe all possible forms of the invention. Rather,the words used in the specification are words of description rather thanlimitation, and it is understood that various changes may be madewithout departing from the spirit and scope of the invention.Additionally, the features of various implementing embodiments may becombined to form further embodiments of the invention.

What is claimed is:
 1. A blind rivet-nut having a setting head and ahollow shaft received in an opening defined by a carrier, wherein thehollow shaft has at a free end opposite the setting head, the free endincludes a first threaded portion that is adapted to receive a threadedelement of a tensioning tool, the hollow shaft having a clamping portionadjacent to the setting head, the clamping portion being adapted to forma bead-like deformation during a setting operation of the blindrivet-nut on the carrier to clamp the carrier between the bead-likedeformation and the setting head, wherein a portion a threadless shaftportion is provided between the clamping portion and the first threadedportion, wherein a self-tapping fastener forms a second thread on thethreadless shaft portion, and wherein the self-tapping fastener isattached in a positive-locking manner to the second thread.
 2. The blindrivet-nut of claim 1, wherein the threadless shaft portion has a holediameter which is smaller than a first diameter of the clamping portionand greater than a second diameter of the first threaded portion.
 3. Theblind rivet-nut of claim 1, wherein a wall of the threadless shaftportion has a thickness sufficient to have an inner thread formed in thewall.
 4. The blind rivet-nut of claim 1, wherein a wall of thethreadless shaft portion has a thickness that is sufficient to resistplastic deformation during a setting operation of the blind rivet-nut onthe carrier.
 5. An assembly comprising: a rivet-nut having a head, afree end, and a sleeve between the head and the free end; a carrierdefining an opening that receives the rivet-nut, wherein the rivet-nutis compressed to form a bead securing the rivet-nut to the carrier; anda self-tapping fastener forming a thread on the sleeve that positivelylocks the self-tapping fastener to the thread.
 6. The assembly of claim5 wherein the rivet-nut is a blind rivet that is deformed by atensioning tool that engages the free end to pull the free end towardsthe head and thereby form the bead.
 7. The assembly of claim 5 whereinthe sleeve has a smooth internal surface until the self-tapping fastenerforms the thread on the smooth internal surface.
 8. The assembly ofclaim 5 wherein the rivet-nut has an internal opening including anintermediate portion formed by a smooth internal surface that defines ahole having a smaller internal diameter than a clamping portion of theinternal opening that is formed into the bead and a greater internaldiameter than an end portion of the internal opening at the free end. 9.A method comprising: assembling a carrier defining an opening to arivet-nut including a hollow shaft having an internal thread on a freeend, a head, and an internal portion between the head and the free end;compressing the rivet-nut by pulling the free end toward the head toform a bead on the opposite side of the carrier from the head; andtapping a thread on the internal portion with a fastener.
 10. The methodof claim 9 further comprising: clamping the carrier between the head andthe bead.
 11. The method of claim 9 wherein the fastener is aself-tapping bolt.
 12. The method of claim 9 wherein the step ofcompressing the rivet-nut is performed by a tensioning tool having athreaded end that is threaded into the internal thread on the free endto pull the free end toward the head and thereby form the bead.